Simplify the following expression: $z = \dfrac{6}{8y} + \dfrac{-4}{8y}$
Solution: Since the expressions have the same denominator we simply combine the numerators: $z = \dfrac{6 - 4}{8y}$ Combine like terms: $z = \dfrac{2}{8y}$ Simplify by dividing numerator and denominator by 2: $z = \dfrac{1}{4y}$